Trace element composition and origin of the atmospheric aerosol in the Norwegian arctic

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Ninety-eight filter samples of < 2.5 μm aerosol were collected in late winter of 1983, 1984 and 1986, and in the summer of 1984 at Ny Ålesund, Spitsbergen and Vardø, Norway, and analyzed for 42 elements. The winter atmospheric concentrations and aerosol compositions were similar at the two sites. In summer, atmospheric concentrations were significantly lower than in winter, particularly at Ny Ålesund and for the metallic pollutants, with elements such as V, Zn, As and Sb exhibiting 20–50 times lower levels than in winter. Application of absolute principal components analysis to the Ny Ålesund winter data yielded three components, which were identified as a general pollution component, crustal dust and sea-salt. Three components were obtained for the aerosol at Vardø as well, but component 1 was here a mixed pollutant/soil dust component, whereas component 2 represented a separate pollution source area, which was identified as the Kola peninsula. This region was responsible for over 70% of the airborne As, Se and In at Vardø. The Ny Ålesund aerosol data were subjected to chemical mass balance source apportionment, using a seven- or eight-element tracer system and regional signatures from eastern North America, Europe and the U.S.S.R. The results indicated that only 10% of the mass of the tracer elements came from eastern North America, and that the U.S.S.R. and Europe contributed in a 60 40 proportion during winter and in a 25 75 proportion in summer. Only 12% of the airborne Se, observed at Ny Alesund in summer, could be attributed to the Eurasian source regions. Evidence is presented that the unexplained Se has a marine, biogenic origin. Arguments are also given to suggest that a sizeable fraction, perhaps up to 50%, of the non-sea-salt sulfate at Ny Ålesund in summer results from gas-to-particle conversion of biogenic, reduced gaseous sulfur species, such as dimethyl sulfide, which are released by the oceans.